The present invention relates to a bearing block or sheave in which a pair of circular rows of ball bearings are disposed between relatively rotatable inner and outer races.
Bearing blocks or pulleys are widely used on sailing craft to control and change the direction of lines, to provide a mechanical advantage, or otherwise adjust the rigging.
With the introduction of small diameter, high strength lines, the sailing industry has developed the need for very small blocks or pulleys. The small diameter line is usually connected to a larger diameter line to facilitate hand operation beyond the pulleys. The lines are used to control various parts of the sailboat rigging without undue clutter. Blocks of this nature have outer sheaves with a diameter down to 16 mm or less.
When dealing with so-called micro blocks, assembly of a number of small parts becomes a problem, but the use of rotary bearings, such as ball bearings is highly desirable, in order to reduce friction around a very small turning radius. Desirably, the block should be light in weight, have high load handling capacity for its size, and utilize bearings to reduce friction.